On the occurrence and enigmatic functions of mixed (chemical plus electrical) synapses in the mammalian CNS

James I. Nagy, Alberto E. Pereda, John E. Rash

Research output: Contribution to journalReview article

9 Scopus citations


Electrical synapses with diverse configurations and functions occur at a variety of interneuronal appositions, thereby significantly expanding the physiological complexity of neuronal circuitry over that provided solely by chemical synapses. Gap junctions between apposed dendritic and somatic plasma membranes form “purely electrical” synapses that allow for electrical communication between coupled neurons. In addition, gap junctions at axon terminals synapsing on dendrites and somata allow for “mixed” (dual chemical + electrical) synaptic transmission. “Dual transmission” was first documented in the autonomic nervous system of birds, followed by its detection in the central nervous systems of fish, amphibia, and reptiles. Subsequently, mixed synapses have been detected in several locations in the mammalian CNS, where their properties and functional roles remain undetermined. Here, we review available evidence for the presence, complex structural composition, and emerging functional properties of mixed synapses in the mammalian CNS.

Original languageEnglish (US)
Pages (from-to)53-64
Number of pages12
JournalNeuroscience Letters
StatePublished - Mar 16 2019



  • Connexins
  • Dye coupling
  • Electrical coupling
  • Nerve terminals
  • Neuronal gap junctions

ASJC Scopus subject areas

  • Neuroscience(all)

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